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CONCLUSIONS AND FUTURE WORK

Dans le document Data Mining: A Heuristic Approach (Page 123-127)

As an alternative to GAs, the application of the EDA paradigm to solve the well- known FSS problem on datasets of a large dimensionality has been studied.

As the application of Bayesian networks is discarded in this kind of large dimension-ality tasks, four simple probabilistic models (PBIL, BSC, MIMIC and TREE) have been used within the EDA paradigm to factorize the probability distribution of best individuals of the population of possible solutions. MIMIC and TREE are able to cover interactions between pairs of variables and PBIL and BSC assume the independence among the variables of the problem. We note that using three of these four probabilistic models (BSC, MIMIC and TREE), GA approaches need more generations than the EDA approach to discover similar fitness solutions. We show this behavior on a set of natural and artificial datasets where these three EDA approaches carry out a faster discovery than the other approaches of the feature relationships and the underlying structure of the problem. In this way, when the wrapper approach is used, this fast discovery of high fitness solutions is highly desirable to save CPU time. However, because of the high CPU times needed for the induction of order-two algorithms in the Internet advertisements domain, the CPU time savings produced by this reduction in the number of solutions relative to GA approaches is noticeably reduced.

As future work, we envision the use of other probabilistic models with large dimensionality datasets, models which assume small order dependencies among the variables of the domain. Another interesting possibility is the use of parallel algorithms to induce Bayesian networks in these kinds of tasks (Xiang & Chu, 1999). When dimensionalities are higher than 1,000 variables, research is also needed on the reduction of CPU times associated with the use of probabilistic order-two approaches.

Biological Data Mining is an interesting application area of FSS techniques

(Ben-Dor, Bruhn, Friedman, Nachman, Schummer, Yakhini, 2000). Ever since efficient and relatively cheap methods have been developed for the acquisition of biological data, data sequences of high dimensionality have been obtained. Thus, the application of an FSS procedure is an essential task.

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Chapter VI

Towards the

Dans le document Data Mining: A Heuristic Approach (Page 123-127)